• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.4
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• pp.423-429
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• 2006

The systems in the ubiquitous computing environment need to provide users with context-aware services, intelligently interacting with the surrounding environment. Therefore, the systems in the ubiquitous computing environment require context-awareness ability in order to gather and analyze context information in various situations and environments. However, existing context-aware systems lack the ability to systematically generate and handle various types of context information, and only a few systems have ability learning from environment. In this paper, a general context model is defined to describe various contexts and a context-awareness framework is implemented based in the model, which makes it straightforward to handle and generate various types of context from diverse sensor. The framework is designed to allow a system to sensed, combined, inferred, and learned context information, in order to provide users with services in dynamic environments. We have implemented the proposed framework and applied it to a u-Health management system.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.12
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• pp.1252-1256
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• 2007

U-learning (ubiquitous learning) systems, which deliver learning materials anytime and anywhere, allow learners to watch live lectures on PDAs, tablet PCs and notebook computers via broadband and wireless Internet. These systems have various problems; first, terminal devices are expensive, and it is difficult to maintain their efficiencies. Secondly, Internet does not guarantee quality of service (QoS), and in general it does not provide real-time services. Finally, the security of these systems is weaker in a local network than in an external network. The USB-based terminal system based on the OSGi service platform was designed as a ubiquitous system, in order to solve those problems. The USB terminals, used in this system, are inexpensive, and it is easy to maintain their performances. Also, this system solves the problems of security in a local network and provides guaranteed QoS. To accomplish this, the number of USB terminals connected to the system has to be limited according to the formula proposed in our paper. This system uses the OSGi specification as a middleware. It supports the discovery mechanism of the USB terminals, maintenance and administration of the system. Finally, this paper shows a driver's license testing system as an example u-learning application1.

• Journal of KIISE:Software and Applications
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• v.34 no.4
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• pp.342-358
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• 2007

Ubiquitous Computing System (UCS) is a system where the user can get information through computer network anytime and anywhere regardless of the places. Since UCS is a personalized system, it should interact with other systems. UCS will bring a remarkable change in production, consumption, politics, economy, community, culture, and other areas related to our daily life. That is, a high-quality UCS results in high-quality services provided to users. Hence, this paper proposes a systematic quality model based on ISO/lEC 9126 in order to evaluate the ubiquitous computing system, based on ISO/lEC 9126. And, we identify key characteristics of UCS and derive the set of quality attributes based on identified characteristics. We define metrics for each quality attribute and Ubiquitous Computing Quality Model CUCQM) so that we can evaluate overall environment and important characteristics of UCS.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.5
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• pp.567-572
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• 2005

Recently, owing to miniaturization of computer and popularization of internet, ubiquitous computing is attracting considerable attention. In ubiquitous environment, user can receive desired information service anywhere, any time. With the advent of ubiquitous age through popularization of internet, it becomes important how to provide user with ubiquitous environment, and what and how to provide to user. In this paper, method to automatically select device most suitable for user in ubiquitous environment is offered. search agents search peripherals, make a list by function, and transmit to serve. Serve learn the transmitted information through intelligent system. If user input information in the form of linguistic according to the list, serve select device suitable for work environment, and compose the system through IP address. This was realize through practical example, experimented and confirmed.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.714-719
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• 2005

In this paper, the informative space is proposed to implant ubiquitous functions into physical spaces. We merge physical and virtual spaces through the space structurization using an RFID system, and solve the space localization and mapping problem for a robot to navigate through the distribution and synthesis of information and knowledge. To distribute knowledge flexibly and reliably to changing environment and also to develop a system which allows a robot to invoke and merge the distributed knowledge more freely, we employ a novel approach of knowledge management based on Web services. The proposed method is verified by building a physical space with two kinds of RFID tags and a virtual space with knowledge database based on Web services.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.3
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• pp.141-152
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• 2007

In this paper, we present a network-oriented lightweight real-time system, which is composed of an event-driven operating system called the Embedded Lightweight Operating System (ELOS) and a generic multi hop ad hoc routing protocol suite. In the ELOS, a conditional preemptive FCFS scheduling method with a guaranteed time slot is designed for efficient real-time processing. For more elaborate configurations, we reinforce fault tolerance by supplementing semi-auto configuration using wireless agent nodes. The developed hardware platform is also introduced, which is a scalable prototype constructed using off-the-shelf components. In addition, in order to evaluate the performance of the proposed system, we developed a ubiquitous network test-bed on which several experiments with respect to various environments are conducted. The results show that the ELOS is considerably favorable for tiny ubiquitous networked systems with real-time constraints.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.145-152
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• 2010

With the recent development of the ubiquitous computing technology, there are increasing interest and research in technologies such as sensors and RFID related to information recognition and location positioning in various ubiquitous fields. Especially, RTLS(Real-Time Locating Services) dealing with spatio-temporal data is emerging as a promising technology. For these reasons, the ISO/IEC published the RTLS standard specification for compatibility and interoperability in RTLS. Therefore, in this paper, we designed and implemented Spatio-temporal Query Processing Systems for efficiently managing and searching the incoming Spatio-temporal data stream of moving objects. Spatio-temporal Query Processing Systems's spatio-temporal middleware maintains interoperability among heterogeneous devices and guarantees data integrity in query processing through real time processing of unceasing spatio-temporal data streams and two way synchronization of spatio-temporal DBMSs. Web Server uses the SOAP(Simple Object Access Protocol) message between client and server for interoperability and translates client's SOAP message into CQL(Continuous Query Language) of the spatio-temporal middleware. Finally, this thesis proved the utility of the system by applying the spatio-temporal Query Processing Systems to a real-time Locating Services.

• The KIPS Transactions:PartA
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• v.12A no.4 s.94
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• pp.273-280
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• 2005

The mobility or highly interconnected and communicating devices and users has implications for the QoS in a ubiquitous computing environment. Therefore, it is important for location aware systems to detect location of mobile object correctly and Provide high quality services in ubiquitous environment. However, it is not easy that location aware systems offer highly reliable QoS to users because process strategies of location aware systems are limited by the capability according to the applied detection target objects. In this paper, we design an autonomic architecture which analyzes the location aware system condition and autonomously chooses the best appropriate process strategy. We also have simulated the Proposed architecture in order to verify its performance. The test results show us that the architecture using self-optimizing mechanism provides higher QoS to users in variable bandwidth.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.281-285
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• 2004

This paper aims to describe how the decision making capability and context-aware computing are jointly used to establish ubiquitous applications. An amended DSS paradigm: CKDDM is proposed in this paper. Under the CKDDM paradigm, a framework of ubiquitous decision support systems (ubiDSS) is addressed with the description of the subsystems within.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.297-300
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• 2005

Especially, system security is very important in the ubiquitous environment. This paper proposes a protecting scheme for security policies in Firewall and intrusion detection system (IDS). The one-way hash function and the symmetric cryptosystem are used to make the protected rules for Firewalls and IDSs. The proposed scheme could be applied in diverse kind of defense systems which use rules.